Do not run Composer as root/super user! See https://getcomposer.org/root for details Authentication required (repo.magento.com):
Username: c1e9e02ac7e11bc1bc83b45cb685b0ba
Password:
Do you want to store credentials for repo.magento.com in /root/.config/composer/auth.json ? [Yn] Y
Installing magento/project-community-edition (2.3.1)